1. Field of the Invention
The present invention relates to tools for straightening or recontouring metal surfaces, and more particularly, to a slide hammer having a spot weldable surface engaging capability.
2. Description of the Contemporary and/or Prior Art
The straightening or recontouring of metal surfaces such as in automobile bodies, when they are dented, is usually accomplished by one of several well known techniques. If possible, the dented surface is impacted on the nonvisible rear side thereof to force the dent outwardly. However, more often than not, this is impractical because of interference from other automobile structure and therefore inaccessibility of the rear side of the dented surface. An alternate method of straightening these bent surfaces is effected by affixing of a tensioning impact tool to the outer surface of the dent and imparting of a tensioning force to the dent to pull the same into the proper configuration.
Devices used in this manner are variously known as slide hammers, slap hammers, impact hammers, etcetera. Such an apparatus is taught in U.S. Pat. No. 2,934,984 issued to Woodman on May 3, 1960. Woodman shows a dent remover which includes a shaft having a tapered threaded portion affixed at one end thereof. The tapered threaded portion is forced through the sheet metal to be straightened or is threaded into a predrilled aperture to affix the end of the tool to the metal. A weight is then shifted on the shaft of the tool to provide the desired pulling effect. Use of this instrument requires the punching or drilling of a hole through the metal to be straightened which later must be filled in and repaired. If the metal which is to be straightened has been flattened against another surface, this tool cannot be employed. An impacting tool which affixes to a metal surface in a similar manner is shown in U.S. Pat. No. 3,519,087 issued to Santi on July 7, 1970.
A variation of this method of engagement is shown in U.S. Pat. No. 3,878,709 issued to Chartier on Apr. 22, 1975. Chartier requires the formation of a hole in the metal surface to be straightened and a hooked element is inserted in the hole engaging the metal so that a pulling force can be imparted thereto. As when the above discussed apparatuses are employed, a hole with the attendant subsequent repair requirement must be employed.
U.S. Pat. No. 3,113,478 issued to Hall, Jr. et al on Dec. 10, 1963 shows a tool for removing auto body dents or the like which is provided with a plurality of chuck engaging footers for engaging the metal surface to be straightened. One configuration of footer is shown to be hook like so as to be inserted in a hole punched through the metal. Another configuration of footer is shown which can be soldered, welded, brazed, or the like to a metal surface. The process of affixing a footer through a separate operation of soldering, welding, brazing, or the like is inconvenient, time consuming, and therefore costly. In addition, the user must manipulate the soldering, welding, or brazing instruments at the same time the tip is kept in position on the metal. Frequently, this may require more than one person, but in any event this is a difficult task for a single individual to easily accomplish. The direct self welding of an impact tool to a metal surface is not shown or suggested.
Other prior art apparatuses which are known teach the welding, brazing, soldering, or threading of a metal stud, washer, or the like to the metal surface to be straightened so that this affixed element can be grasped or otherwise captured by a slide hammer or the like to impart a pulling force or a pushing force on the metal to be straightened. As in Hall, this requires a two-step process which is awkward and at best time consuming. U.S. Pat. No. 3,791,012 issued to Jenkin on Feb. 12, 1974 teaches an impact device which clamps onto a threaded stud threadably engaged in an aperture disposed in a work piece.
U.S. Pat. No. 3,801,772 issued to Curcio et al on Apr. 2, 1974 teaches a tool for repairing an indented surface of a sheet metal panel wherein the tool includes a stud welder for welding a stud to a metal panel and a gripping apparatus for pulling on the stud once it is welded into position. As in other stud welding and pulling apparatuses, everytime the device is used, the stud must be engaged by the tool, the tool must be used to weld the stud in position, the stud must be clamped in the tool, and then the pulling force must be exerted on the stud. Although in some respects effective, it shall become apparent that the present invention accomplishes this in a single operation.
Other apparatuses such as those shown in U.S. Pat. Nos. 3,825,717 issued to Hughes, Jr. on July 23, 1974; and 4,103,140 issued to Glatthorn on July 25, 1978 impact a stud to effect contact with a metal surface or to position the stud as desired and then subsequently weld the stud to a surface. Although these devices perform functions which are individually similar to the present invention and other prior art devices, these functions are not aggregated in the same serial relationship as the present invention and therefore perform in a quite different manner for quite different purposes. In addition, these apparatuses do not teach the direct self welding of an impact tool to a work piece.
U.S. Pat. No. 3,959,619 issued to Schill on May 25, 1976 shows as apparatus for straightening bent metal surfaces wherein an electrode is brought into contact with the metal surface to be straightened in a series of hammer blow-like movements which heat up the metal to a high temperature. This heating allegedly causes the metal to return to its original undented shape. The electrode is never welded to the metal surface, but is merely used to melt small openings in the surface to relieve the stresses therein. As in other devices previously discussed, after the panel is returned to its proper shape, it is perforated with numerous openings all of which must be repaired. Additionally, it is well known in the art that if sheet metal is bent severely enough, it stretches and no amount of heating can put it back into the proper shape since the metal has been stretched in the bending process.
The present invention overcomes all of the mechanical as well as time element shortcomings of the prior art by providing a tool for recontouring metal which is used in conjunction with an electrical welding apparatus. A portion of the tool is welded directly to the surface to be straightened and, through the use of slidable means which creates both compression and tension forces as desired, it can be easily and quickly employed to reposition the metal surface as desired. After repositioning of the metal surface, the tool is merely twisted to release the previously created weld so that the tool can be employed elsewhere as desired.